首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   352篇
  免费   20篇
  2024年   3篇
  2023年   11篇
  2022年   1篇
  2021年   4篇
  2020年   14篇
  2019年   15篇
  2018年   37篇
  2017年   39篇
  2016年   27篇
  2015年   16篇
  2014年   22篇
  2013年   99篇
  2012年   5篇
  2011年   11篇
  2010年   8篇
  2009年   6篇
  2008年   10篇
  2007年   4篇
  2006年   1篇
  2004年   2篇
  2003年   2篇
  2002年   1篇
  2001年   4篇
  2000年   3篇
  1999年   2篇
  1998年   3篇
  1997年   2篇
  1996年   2篇
  1995年   1篇
  1993年   2篇
  1992年   2篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   3篇
  1986年   1篇
  1985年   1篇
  1982年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1957年   1篇
排序方式: 共有372条查询结果,搜索用时 15 毫秒
291.
During the first half of the twentieth century, despatches about the coldest corner of the British Empire were circulated to three, sometimes four, of its southern neighbours under the British crown: Australia, New Zealand, South Africa and the Falklands. Of these four, South Africa seemed the least interested in Antarctica, despite the keen interest of some influential individuals and a strategy of bringing Antarctica into the imperial fold through British dominions that were proximate to Antarctica. In this context, we ask how South Africa viewed itself in relation to the Antarctic to the south and the British metropole to the north. We discuss the key activities that connected South Africa to Antarctica—whaling and weather forecasting. Moreover, we consider some of the enterprising plans for a South African National Antarctic expedition, and what these plans reveal of South Africa's perception of itself as a southern country. This article interlinks with a growing scholarship that is critical of treating Antarctic history as politically and culturally isolated, including showing how the relatively simple natural and political ecology of the Antarctic can throw into relief multiple national and international concerns.  相似文献   
292.
A new microdomatid gastropod, Eopagodea sevillana gen. and sp. nov., is described from the Late Ordovician (pre-Hirnantian Ashgill) limestones of Seville, Ossa Morena Zone, Spain. Palaeozoic microdomatids lived in shallow-water environments and were restricted to warm-water regions. Occurrence of microdomatid gastropods in the pre-Hirnantian Ashgill limestones of the Cerrón del Hornillo syncline (Ossa Morena Zone, Spain) is interpreted as an example of an influx of warm-water faunal elements into the otherwise cool to cold climate of the Mediterranean region during a short-termed, pre-Hirnantian increase of palaeotemperatures. The Late Ordovician microdomatid genus Daidia Wilson, 1951, is revised and two new Late Ordovician (Ashgill) subspecies of Daidia cerithioides (Salter, 1859) are described: Daidia cerithioides sewardensis n. subsp. from the Don River area of the York Mountains, Seward Peninsula, western Alaska, and Daidia cerithioides wilsonae n. subsp. from the Little East Lake Formation of northwestern Maine.  相似文献   
293.
O’Gorman, J.P., Otero, R.A. & Hiller, N., 2014. A new record of an aristonectine elasmosaurid (Sauropterygia, Plesiosauria) from the Upper Cretaceous of New Zealand: implications for the Mauisaurus haasti Hector, 1874 Hector, J., 1874. On the fossil Reptilia of New Zealand. Transactions and Proceedings of the New Zealand Institute 6, 333358. [Google Scholar] hypodigm. Alcheringa 38, 504–512. ISSN 0311-5518

An indeterminate aristonectine elasmosaurid is recorded from a lower Maastrichtian bed of the Conway Formation, Waipara River, South Island, New Zealand. The described specimen (CM Zfr 104), previously considered part of the hypodigm of Mauisaurus haasti, came from the upper part of the Alterbidinium acutulum biozone, the same zone from which the only well-known aristonectine from New Zealand, Kaiwhekea katiki, is recorded. The cervical vertebrae of CM Zfr 104 have the same distinctive features (i.e., with extremely broad rather than long centra) as those from previously recorded juvenile aristonectines from Argentina, Chile and Antarctica. This new record is congruent with the biogeographic relationships of Cretaceous marine amniotes from the Weddellian Palaeobiogeographic Province (i.e., Patagonia, western Antarctica, New Zealand and southeastern Australia). Therefore, this type of vertebra is regarded as a distinctive feature of the Weddellian aristonectine elasmosaurids.

José P. O’Gorman [], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina; [CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas)]; Rodrigo A. Otero [], Red Paleontológica U-Chile. Laboratorio de Ontogenia y Filogenia, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Av. Las Palmeras 3425, Santiago, Chile; Norton Hiller, [], Department of Geological Sciences, University of Canterbury, PB 4800, Christchurch, 8001, New Zealand and Canterbury Museum, Rolleston Avenue, Christchurch, New Zealand, 8013.  相似文献   
294.
Seven species of marine bivalves, including six new taxa, are described from the Cape early Miocene Melville Formation which crops out on the Melville Peninsula, King George Island, West Antarctica. The bivalve assemblage includes representatives of the families Nuculidae, Ennucula frigida sp. nov., E. musculosa sp. nov.; Malletidae, Neilo (Neilo) rongelii sp. nov.; Sareptidae, Yoldia peninsularis sp. nov.; Limopsidae, Limopsis psimolis sp. nov.; Hiatellidae, Panopea (Panopea) sp. cf. P. regularis; and Pholadomyoida (Periploma acuta sp. nov.). Species studied come from four sedimentary sections measured in the upper part of the unit. Detailed morphologic features of nucloid and arcoid species are exceptionally well preserved and allow for the first time reconstruction of muscle insertions as well as dentition patterns of Cenozoic taxa. Known geological distribution of the species is in agreement with the early Miocene age assigned to the Cape Melville Formation. The bivalve fauna from Cape Melville Formation is the best known from Antarctic Miocene rocks, a time of complex geologic, paleogeographic and paleoclimatic changes in the continent. The new fauna introduces new taxonomic and palaeogeographic data that bear on the question of opening of sea gateways and distribution of Cenozoic biota around Antarctica.  相似文献   
295.
With the break-in in the Egyptian Museum at the height of the ‘Lotus Revolution’ in January 2011 many heritage experts thought they saw their worst dreams come true: another ‘cradle of civilization’ threatened. One and a half years later the ‘½ Revolution’ did not bring the Egyptians the much desired prosperity. In the contrary, much seems to be worse than before January 2011 and unfortunately the heritage sector is no exception. Massive looting arose after the revolution and continues till today. This article tries to answer who these looters are and why the plunder of archaeological sites continues. Yet, many locals defended the sites in their vicinity. How come the local population felt connected to this heritage. For over 10 years they have been forbidden to enter the sites and the authorities even consider them a nuisance who need to be hidden for the massive tourist industry. The post-colonial narrative sheds much light on all these questions. It is noted that there is a huge lack of local involvement in Egyptian heritage as well as an almost absent scientific involvement of local scholars in Egyptology. There are signs that with the new government this will change. Firstly, western Egyptologists seem to realize they need to pay more attention to public/community archaeology and secondly, it is expected that Islamic heritage will be stressed in the coming years perhaps at the cost of Egyptology.  相似文献   
296.
Interaction between hominins and carnivores has been common and constant through human evolution and generated mutual pressures similar to those present in worldwide modern human-carnivore conflicts. This current interaction is sometimes violent and can be reflected in permanent skeletal pathologies and other bone modifications. In the present paper, we carry out a survey of 124 forensic cases of dangerous human-carnivore encounters. The objective is to infer direct hominin-carnivore confrontation during the Pleistocene, which is important to understand behavioral changes during human evolution. In addition, the case of Neanderthals is analyzed in order to find evidence of past attacks using forensic observations. The results obtained pose that Neanderthals could potentially have been involved in dangerous encounters during the Pleistocene, validating our methodology to approach past attacks from a forensic perspective.  相似文献   
297.
At present, several obstacles to tourism development have been identified in developing countries. These include: poor infrastructure; shortage of facilities; a weak tourist image; a lack of know‐how with regard to how to welcome visitors and market tourism services; and the scarcity of available capital. In the research reported on in this paper, we explore the involvement of microcredit institutions to alleviate these issues. Because tourism is not yet developed in our study area of West Cameroon, action research was considered the only way to validate (by action) the recommendations of both the actors and the researchers. Action research permits the researchers to study the complex issues that typify the management of tourist destinations, including, for example, governance problems. It allows for networking and capacity to change the ways in which actions are carried out. The paper explores possible synergies between microfinance institutions (MFIs) and small and medium tourism businesses in an African rural community. First, we emphasise the obstacles to the formation of partnerships between MFIs and tourism businesses and we suggest ways to minimise them. Second, we describe how we facilitated networking between tourism actors and MFIs, which enabled the development of tourism products through new partnerships. As a result, four businesses are currently operating. From a research perspective, we point out the strengths and weaknesses of different types of associations and list the challenges. The results indicate that asymmetry of information and a lack of entrepreneurial spirit emerge as key concerns. The action research has promoted place and community based development. However, we underline that proper tourism development also requires the participation of stakeholders acting at different spatial scales.  相似文献   
298.
In the wake of the current revival of the historiography of racism, this article focuses on the claim that Aristotle is the progenitor of the concept in the West. If a purely textual analysis of Aristotelian political writings can lead to such a conclusion, the historicising of these writings leads to a different result. Rejecting the idea that the normative function of the work of Aristotle is limited to the Athenian polis, this article demonstrates that the imperial context should serve as an ‘available light’ by which the meaning of certain Aristotelian key concepts, including nature, the ‘divine man’ and the natural slave. In doing so, the central role of prohairesis in Aristotle's conception of human nature is highlighted.  相似文献   
299.
This paper is a discussion of how and why film should be considered heritage, by analysing the role of the Cannes Film Festival (CFF) in turning films into a form of heritage, through a number of different initiatives focused on the preservation and promotion of films as heritage. In doing so, the present article charts the evolution of the CFF against the background of cultural diplomacy and heritage. Studying the CFF from a heritage perspective will contribute to theoretical debates that situate film festivals as places where memories and identities are contested and negotiated. The paper will show that these heritage-making initiatives are a result of the ability of the CFF to respond to changes taking place in an age of international contact, to accommodate new trends, new films and emerging national film industries. Within this context, this paper also addresses a gap in film festival scholarship by engaging in heritage theory to further expand cultural and heritage insights.  相似文献   
300.
Covering the knowledge economy scenario, this article attempts to illustrate the analysis of the employment of knowledge transmission channels in the EuroClusTex, cross-border textile and clothing cluster between northern Portugal and Galicia. Therefore, an exploratory research was conducted. Primary data were obtained through participation in events, from interviews with key informants (entrepreneurs, leaders of cluster support institutions and government representatives). The secondary data were provided by the cluster support institutions, international organizations and the literature review. The results showed that EuroClusTex contributes to the competitiveness of regions, boosting trade relations between Galicia and northern Portugal. The most effective knowledge transmission channels in EuroClusTex were identified as: imitation, relationship with suppliers, public policy and human resources training. Experiences similar to EuroClusTex can be considered and served as examples for the development of clustering policies in other countries.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号